Carriers for weft insertion by the rapier principle with positive gripping for shuttleless looms

ABSTRACT

This invention relates to a carrier for weft insertion by the rapier principle in a shuttleless loom which mounts two independent gripper units and a differential control system operatively connected with said two gripper units. The carrier preferably includes a main portion and a control finger movably mounted on said main portion and adapted to be actuated by a cam, each said gripper unit includes a fixed jaw which is an integral part of said main portion of the carrier, and a movable jaw, and said differential control system includes a swingle bar the two ends of which are engaged one in said movable jaw of each said gripper unit and the central part of which is engaged in said movable control finger.

[ 1 Jan. 21, 1975 CARRIERS FOR WEFT INSERTION BY THE RAPIER PRINCIPLE WITH POSITIVE GRIPPING FOR SHUTTLELESS LOOMS [75] Inventor: Georges Scheidecker,Mulhouse,

France [73] Assignee: Societe Alsacienne De Constructions Mecaniques De Mulhouse, Mulhouse Cedex, France 22 Filed: Oct. 16, 1973 21 Appl. No.: 406,868

[30] Foreign Application Priority Data Oct 17, 1972 France 72.36658 [52] US. Cl 139/122 N [51] Int. Cl D03d 47/20 [58] Field of Search 139/122 R, 122 N, 125

[56] References Cited UNITED STATES PATENTS 3,390,707 6/1968 Schcrillo 139/122 N 3,695,306 10/1972 Kimura et al. 139/125 Primary Examiner-Henry S. Jaudon Attorney, Agent, or FirmHolman & Stern [57] ABSTRACT This invention relates to a carrier for weft insertion by the rapier principle in a shuttleless loom which mounts two independent gripper units and a differential control system operatively connected with said two gripper units. The carrier preferably includes a main portion and a control finger movably mounted on said main portion and adapted to be actuated by a cam, each said gripper unit includes a fixed jaw which is an integral part of said main portion of the carrier, and a movable jaw, and said differential control system includes a swingle bar the two ends of which are engaged one in said movable jaw of each said gripper unit and the central part of which is engaged in said movable control finger.

8 Claims, 8 Drawing Figures FATENTEU JAN 2] I975 SHEET 2 OF 2 CARRIERS FOR WEFT INSERTION BY THE RAPIER PRINCIPLE WITII POSITIVE GRIPPING FOR SHUTTLELESS LOOMS FIELD OF THE INVENTION The invention relates to carriers for weft insertion by the rapier principle with positive gripping for shuttleless looms.

BACKGROUND OF THE INVENTION The correct gripping of the weft yarns when inserted by the rapier principle in shuttleless looms presents difficulties, particularly when these threads have irregularities, for example, when they are what are known as slubby yarns, knotty yarns, neppy yarns, etc.

In an attempt to overcome these difficulties, use has already been made of rigid double grippers, that is grippers having two-armed jaws which may or may not be controlled, but which in any case operate at all time in perfect synchronism because of their rigidity; grippers of this kind are not satisfactory because, when they have to grip a weft thread which has an extra thick section, one possible consequence is fraying of the thread as a result of slippage of said thickness over the core of the thread, with the result that the core of the thread, which is insufficiently gripped, escapes from the gripper and only the surplus material, be it the knot, the nep, or the slub is carried along. The result is a flaw in the fabric produced or else a stoppage of the machine.

In an improved device hitherto proposed, the carrier has two independent gripper units each subjected to an elastic tightening force. There is thus better gripping of the weft yarn or thread, but nonetheless it is dependent on the adjustment of the pressure of the return spring of each of the two grippers; it is particularly in the gripping of the thread as it leaves the weft-insertion carrier that the weaknesses of the device are apparent since the closing of the two grippers is controlled by a cam which releases, on the occasion of closing of the grippers, the springs which had been put under tension by the same cam upon opening of the grippers. In these conditions, if the jaws of one of the grippers come into pressure contact with any extra-thick part of the weft thread, they effectively grip said thread a little sooner than the jaws of the other gripper since the latter has to close further to come into pressure contact with a thinner section of thread. The effective moment of grip on the thread is not therefore precisely the same for both grippers, with the result that the position of the weft thread in the grippers is not perfectly controlled and it is therefore necessary to provide a considerable overlap between the weft-insertion carrier and the weft-withdrawal carrier at the time of transfer. Moreover, if a thicker section of the weft-thread occurs in the gripper strand remote from the bobbin, this gripper first of all pulls the thick section with the result that the end of the weft thread may escape from the gripper since the other gripper closes with a delay.

SUMMARY OF THE INVENTION The object of the invention is to provide a carrier supplying weft-thread with controlled gripping, which includes two independent gripper units, and which does not have the aforementioned disadvantages of the carriers hitherto proposed or known.

According to the present invention, we provide a carrier for weft insertion by the rapier principle in a shuttleless loom, said carrier having two independent gripper units subject to the action of a differential control system for balancing the gripping force at the two grippers.

Owing to the two gripper units being subject to the action of a differential control system, even if the two parts of the weft-thread gripped, respectively, in the two gripper units are not of precisely the same diameter, they are gripped with exactly the same pressure in the two gripper units; the effective gripping of the two parts of the weft-thread in the two respective gripper units, occurs at precisely the same instant since the differential system of control can only exert pressure in one of the gripper units when an equal pressure is exerted in the other gripper unit. The gripping of the weft-threads is thus very effective and their positioning in the gripper units is exact and regular.

In a preferred embodiment, each gripper unit includes a fixed jaw which is an integral part of a main portion of the carrier, and a movable jaw, and the differential control system includes a swingle bar the two ends of which are engaged one in each of the two movable jaws and the central part of which is engaged in a movable control finger adapted to be pushed back by a cam.

The invention will be better understood by reading the description which follows and by examining the accompanying drawings which show, by way of nonlimiting examples, two embodiments of weft-supplying in accordance with the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In these drawings:

FIG. 1 is an elevation, with cutaway sections, of a first embodiment;

FIG. 2 is a plan view corresponding to FIG. 1;

FIGS. 3 and 4 are transverse sections along the lines III--III and IV--IV, respectively, of FIG. 2;

FIG. 5 is an elevation of another embodiment;

FIG. 6 is a plan view corresponding to FIG. 5;

FIGS. 7 and 8 are transverse sections along the lines VII-VII and VIIIVIII, respectively, of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The carrier for weft insertion by the rapier principle with positive gripping for a shuttleless loom, shown in particular in FIGS. 1 and 2, comprises a main portion 1 on which are arranged two independent gripper units comprising, respectively, two movable jaws 2 and 3 co operating with two fixed jaws 4 and 5 respectively, which are integral parts of the main portion 1 of the weft-insertion carrier.

The two movable jaws 2 and 3 are articulated on a common transverse spindle 8 (see also FIG. 4) supported, by its two extremities, in two lateral cheeks 11 and 12 on the main portion 1 of the carrier.

The two movable jaws 2 and 3 are operated by a differential control system including operating means made up by a movable control finger l4 and forcetransmitting means including a swingle bar 15 (see also FIG. 3). The movable control finger 14 comprises a suitably shaped plate also mounted on the spindle 8 between the two movable jaws 2 and 3 of the gripper units so that it can pivot. Between the control finger l4 and the two movable jaws 2 and 3 are interposed spacer disks l8 and 19, respectively, in such a way that the lateral faces of the two jaws 2 and 3 bear against the inter nal faces of the two cheeks 11 and 12 respectively, of the main portion of the carrier and thus suitably guided.

The swingle bar 15 comprises a rod, the central part of which is freely engaged in a hole 22 in the movable control finger l4 and the two ends are freely engaged, respectively, in two holes 23 and 24 formed in the two movable jaws 2 and 3. For optimum operation of the device the three holes 22, 23 and 24 are preferably countersunk at both of their ends. The rod 15 is confined, with some play, between the two cheeks 11 and 12 of the main portion of the carrier, in such a way that it is positioned axially without its being necessary to provide any special supplementary means for this purpose.

The two movable jaws 2 and 3 are urged resiliently towards their opening position by a helical spring 27, one end of which is supported on a projecting boss 28 on the main portion 1 of the carrier and the other end of which bears against the movable control finger 14 on which it is centred by a stub pin 29 integral with said control finger.

Finally, between each of the two movable jaws 2 and 3 and the main portion 1 of the carrier is interposed a resilient abutment for limiting the opening of each gripper unit. In this embodiment, each of these two resilient abutments is formed by a resilient tongue, such as 32 for the movable jaw 3, the root of which is an integral part of the movable jaw 3, while its free extremity comes to bear against the main portion 1 of the carrier at the end of the opening movement of said movable jaw. This tongue is obtained, for example, by simply forming, in the corresponding part of the moving jaw, a slot such as 33.

The other movable jaw 2 is furnished with a resilient tongue indentical with the tongue 32 and coinciding with the latter in FIG. 1.

Against the main portion 1 of the weft-insertion carrier is secured a sole-plate 36, for example of wood or fibre, intended to brush against the reed.

The operation of the gripper units is as follows:

Under the action of the spring 27, the movable finger 14 is urged to pivot around the spindle 8 in the direction of the arrow fl (FIG. 1) so that, through the intermediary of the swingle bar 15, it tends to cause the two jaws 2 and 3 of the two gripper units to pivot around the same spindle 8 in the same direction fl; the free ends of said jaws are therefore applied against the associated fixed jaws 4 and with two forces which are always equal owing to the intervention of the swingle bar 15 in the control. When, in operation, the weftinsertion carrier travels in the direction of the arrow f2 to grip and then insert into the shed a weft thread 10, the movable control finger 14 comes up against a fixed cam 35 which causes the simultaneous opening of the two grippers. As soon as the action of the cam ceases, the released spring 27 pushes the control finger 14 away and the latter pivots in the direction of arrow fl and closes off the two movable jaws 2 and 3 on to the weft thread which is squeezed against the associated fixed jaws 4 and 5. Owing to the balancing of the gripping forces which is automatically established through the action of the swingle bar 15, the two parts of the thread 10 are effectively gripped respectively in the two gripper units, with exactly the same force, irrespective of the differences in thickness of these two parts of the thread, that is, especially if there is a flaw in one of them. When the weft-insertion carrier which is moving through the warp shed from the right-hand or weftsupply side of the loom meets approximately half-way across the shed, the weft-withdrawal carrier simultaneously moving through the shed from the left-hand side of the loom, the weft yarn is transferred from the weft-insertion carrier to the weft-withdrawal carrier and the carriers then reverse direction and return to their respective sides of the loom again.

The resilient abutment tongues 32 can absorb differences in the settings of the machine and in the successive strokes of the weft-insertion carrier without damage to the mechanism, while however positioning in a very satisfactory manner the movable jaws 2 and 3 in their maximum opening position.

In FIGS. 5 to 8 there is shown another embodiment which differs from that of FIGS. 1 to 4 only in that the movable control finger 1411, instead of being articulated on the same spindle as the movable jaws of the grippers, is articulated on a spindle 41 separate from the spindle 8 for pivoting of the jaws. In the example shown, this spindle is mounted in two auxiliary cheeks 42 and 43 integral with the main portion 1 of the carrier. The two movable jaws 2 and 3 of the grippers are positioned axially by a single central tubular spacer 45 engaged over the spindle 8.

The mechanism of this modification operates in the same way as that of FIGS. 1 to 4 and enables the arrangement of different leverages between the movable control finger 14 and the movable jaws 2 and 3 of the grippers, depending on the applications envisaged.

Naturally the invention is not limited to the embodiments described and illustrated, and it is possible to make modifications therein, depending on the applications envisaged, without in so doing departing from the scope of the invention as defined in appended claims.

What is claimed is:

1. A carrier for weft insertion by the rapier principle in a shuttleless loom, said carrier mounting two independent gripper units; and a differential control system including operating means including a single forcetransmitting means including means for equalizing the gripping force of the two gripper units and which is operatively connected to said two gripper units whereby gripping forces of the gripper units on a weft thread are equalized irrespective of weft thread imperfections.

2. A carrier as set forth in claim 1 including a main portion and a control finger movably mounted on said main portion and adapted to be actuated by a cam, each said gripper unit including a fixed jaw which is an integral part of said main portion of the carrier, and a movable jaw, said differential control system forcetransmitting means comprising a swingle bar including two ends which are respectively engaged in one said movable jaw of each said gripper unit, the central part of the swiggle bar being engaged in said movable control finger.

3. A carrier as claimed in claim 2, including a spring normally urging movement of said movable control finger in the direction to close said gripper units.

4. A carrier as claimed in claim 3, in which said main portion of said carrier includes two cheeks traversed by a spindle on which said two movable jaws are mounted for pivotal movement, said control finger being mounted for pivotal movement on said main portion of said carrier between said two movable jaws, said swingle bar passing freely through a hole in said control finger and two holes in said movable jaws and being mounted against axial movement between said two cheeks.

5. A carrier as claimed in claim 4, in which said two movable jaws and said control finger are mounted for pivotal movement on the same spindle.

6. A carrier as claimed in claim 4, in which said two movable jaws and said control finger are respectively mounted for pivotal movement on separate spindles on the carrier.

movable jaw. 

1. A carrier for weft insertion by the rapier principle in a shuttleless loom, said carrier mounting two independent gripper units; and a differential control system including operating means including a single force-transmitting means including means for equalizing the gripping force of the two gripper units and which is operatively connected to said two gripper units whereby gripping forces of the gripper units on a weft thread are equalized irrespective of weft thread imperfections.
 2. A carrier as set forth in claim 1 including a main portion and a control finger movably mounted on said main portion and adapted to be actuated by a cam, each said gripper unit including a fixed jaw which is an integral part of said main portion of the carrier, and a movable jaw, said differential control system force-transmitting means comprising a swingle bar including two ends which are respectively engaged in one said movable jaw of each said gripper unit, the central part of the swiggle bar being engaged in said movable control finger.
 3. A carrier as claimed in claim 2, including a spring normally urging movement of said movable control finger in the direction to close said gripper units.
 4. A carrier as claimed in claim 3, in which said main portion of said carrier includes two cheeks traversed by a spindle on which said two movable jaws are mounted for pivotal movement, said control finger being mounted for pivotal movement on said main portion of said carrier between said two movable jaws, said swingle bar passing freely through a hole in said control finger and two holes in said movable jaws and being mounted against axial movement between said two cheeks.
 5. A carrier as claimed in claim 4, in which said two movable jaws and said control finger are mounted for pivotal movement on the same spindle.
 6. A carrier as claimed in claim 4, in which said two movable jaws and said control finger are respectively mounted for pivotal movement on separate spindles on the carrier.
 7. A carrier as claimed in claim 2, including resilient abutments interposed between each movable jaw and said main portion of said carrier to limit the opening of each said gripper unit.
 8. A carrier as claimed in claim 7, in which said resilient abutments comprise a resilient tongue, the root of the tongue being an integral part of the associated movable jaw, the tongue having a free extremity which is engagable against said main portion of said carrier at the end of the opening movement of said associated movable jaw. 